vacuum pumps

bigwhisky · Mon Jul 18, 2005 3:24 pm

Bigwhisky dreams of iso, then hcl performic. However, bigwhisky is so confused by this pump thing.

Bigwhisky has been esp ing pump companies for the last few days and in this part of the world a 2 stage diaphragm pump with teflon coating runs to approx $1700US. Hey, i am not even 100% sure if i should be chasing a pump of this kind, so any advice is appreciated?

What i do know is that oil filled pumps should be passed on.

Some one offered me a 'wobble pump' by DVP it pulls 10mbar, my research leads me to think that these are similar to diaphragm pumps but i am not 100% sure.

Am starting to think of water aspiration again but am so unsure weather these are suitable for the dreams of the first sentence. The one pictured on Rhodiums site by polythenesam looks cool.

i have done heaps of reading here but am still lost so please help.
send me your address and i will come wash your car.

bigwhisky.

java · Consumer

Try to read about all the different types here, and also this is an interesting pump.....java

http://www.brandtech.com/vacbrand/mz2c2ak.shtml

bigwhisky · Thu Aug 18, 2005 4:40 pm

I have been google searching etc and am a bit confused between as to the differences between a single or double stage oil pump. Is one preferable to the other in terms of effectiveness and maintenance?

Anyone ever dreamed a sargent welch 8814A in effect?

-bigwhisky

biobrew · Fri Aug 19, 2005 12:45 am

no experience with a sargent welch 8814A, but swim has a fisher maxima c+ corrosion resistant oil pump that will pull sassy over at about 50C with fresh oil...great pump

bio · Working Bee

Dual stage pulls higher vacuum and means 2 elements in series. They allow a interstage vent (gas ballast) used to minimize vapor condensing in the pump (oil). Most all pumps will be 2 stage for your application.

Oil pumps are fine if used correctly. Destroy your rotary vane unit quickly by distilling solvents or wet organics.

A decent refrigeration vac pump (2stage w/ gas ballast) can be had from $200-500 and will pull 25-59microns (theoretically)

Stinging_Nettle · Mon Sep 26, 2005 4:22 pm

SWISN has got a vacuum pump that cost ~$500 US currency. It was a used item that he got through a supplier and was initially used by Shell. Granted it is not the most powerful pump nor is it silent in its operation. However it is easy to use having an entry and exit valve that one can attach tubing to. Therefore SWINE can use it for flash chromatography since it is dual purpose. As far as vacuum distillation goes it is only really good for removing solvents and the like. I mean theoretically one could distill their safrole from it but in terms of getting MDP2P then it is about as effective as an aspirator.

methyl_ethyl · Riedel De Haen

If your just starting out don't waste your money on a diaphragm pump. At least with an oil pump you can change your oil often, in conjunction with the gas ballast open. If you start out with a diaphragm pump you will surely destroy it, by introducing vapours into it.

Wait and purchase a diaphragm pump when you know exactly when and where they are best utilized, and how to keep vapours from being introduced into the pump.

With an oil pump you are afforded a much larger margin for error, which is good when you are learning given the higher cost of a good diaphragm pump.

m_e

anime · Wed Sep 28, 2005 3:00 am

Yellow jacket...MDP2P will come over at 99-100C

methyl_ethyl · Riedel De Haen

RoundBottom · Wed Sep 28, 2005 5:31 am

realize that a good pump isn't worth much if you can't tell what pressure you're at. a good (calibrated!!) vacuum gauge is as important as a good pump.

hAzzBEEn · Wed Sep 28, 2005 7:53 pm

A +/- 2% vacuum guage is less than $10 (but has brass connection). A +/- 1% glycerin filled vacuum guage is just over $15 (but has brass connection). These can easily be fitted to just about any pump. Most pumps that SWIh has seen have either an NPT threaded connection or a barbed fitting that is screwed into an NPT female connection. The barbed connection can be removed, and the appropriat SS pipe nipple be screwed in with some teflon tape, and "T" with the guage attached. Then a barbed-to mail NPT fitting can be screwed into the other part of the T. For folks that aren't familiar with the fittings, etc., just go to a hardware store and look at the pipes and fittings. It's really straightforward. Most stores in SWIh's area don't stock the stainless steel fittings, etc. The most likely won't have the vacuum pressure guage that measures in Hg. They can be ordered, easily.

For corrosive applications one would need a guage with a stainless steel connection. SWIh has seen them ranging from $50 to $100+.

SWIh's quesiton is, do most folks use vacuum pressure regulators with their pumps or do they just make due with the pressure that the pump provides. What kind of vacuums can standard glassware handle? Vacuum regulators can be expensive. SWIh hasn't seen one for corrosive applications, yet (he hasn't looked very hard either).

methyl_ethyl · Riedel De Haen

ApprenticeCook · DILLIGAF

hey m_e where did you get the digital sensor and guage from? ive been looking around but cant seem to find vacuum, all i can find is digital pressure (+ve only, doesnt go into vacuum)... or more to the point, where would i most likely be able to find your setup? did you ghetto the claisen like adaptor or was that part of it?
Sounds good i would like to see pictures please!

-AC

Spacemonkey · Sun Oct 02, 2005 5:36 pm

Digital vacuum gauges are an important part of an AC/refrigerant systems technicians toolkit. Much like the veritable "stinging" rotary vane oil pump that's so famous in these parts.

methyl_ethyl · Riedel De Haen